title: Dispersal network structure and infection mechanism shape diversity in a coevolutionary bacteria-phage system.
abstract: Resource availability, dispersal and infection genetics all have the potential to fundamentally alter the coevolutionary dynamics of bacteria-bacteriophage interactions. However, it remains unclear how these factors synergise to shape diversity within bacterial populations. We used a combination of laboratory experiments and mathematical modeling to test how the structure of a dispersal network affects host phenotypic diversity in a coevolving bacteria-phage system in communities of differential resource input. Unidirectional dispersal of bacteria and phage from high to low resources consistently increased host diversity compared with a no dispersal regime. Bidirectional dispersal, on the other hand, led to a marked decrease in host diversity. Our mathematical model predicted these opposing outcomes when we incorporated modified gene-for-gene infection genetics. To further test how host diversity depended on the genetic underpinnings of the bacteria-phage interaction, we expanded our mathematical model to include different infection mechanisms. We found that the direction of dispersal had very little impact on bacterial diversity when the bacteria-phage interaction was mediated by matching alleles, gene-for-gene or related infection mechanisms. Our experimental and theoretical results demonstrate that the effects of dispersal on diversity in coevolving host-parasite systems depend on an intricate interplay of the structure of the underlying dispersal network and the specifics of the host-parasite interaction.
authors.affiliation: Biosciences, University of Exeter, Exeter, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Sieber
authors.affiliation: Department of Mathematics, Imperial College London, London, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Robb
authors.affiliation: Ecology and Evolutionary Biology Department, University of California, Santa Cruz, CA, USA. forde@biology.ucsc.edu.
authors.forename: Samantha E
authors.initials: SE
authors.lastname: Forde
authors.affiliation: Biosciences, University of Exeter, Exeter, UK. I.Gudelj@exeter.ac.uk.
authors.forename: Ivana
authors.initials: I
authors.lastname: Gudelj
mesh_terms: D017903:Bacteriophage T3 / Q000235:genetics*; D005075:Biological Evolution; D004926:Escherichia coli / Q000235:genetics* / Q000821:virology*; D054884:Host-Pathogen Interactions; D008070:Lipopolysaccharides / Q000378:metabolism; D008957:Models, Genetic
chemical_list: D008070:Lipopolysaccharides